TREEISO - Tree Isomorphism

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Given two undirected trees T1 and T2 with equal number of vertices N (1 ≤ N ≤ 100,000) numbered 1 to N, find out if they are isomorphic.

Two trees T1 and T2 are isomorphic if there is a bijection f between the vertex sets of T1 and T2 such that any two vertices u and v of T1 are adjacent in T1 if and only if f(u) and f(v) are adjacent in T2.

Input

The first line of input contains the number of test cases nTest (1<= nTest <= 400). Each test case contains:

• The first line contains the number of nodes N.
• Each of next N-1 lines contain two integers A, B, denoting that there is an edge in T1 between nodes A and B (1 ≤ A, B ≤ N).
• Each of next N-1 lines contain two integers A, B, denoting that there is an edge in T2 between nodes A and B (1 ≤ A, B ≤ N).

The sum of N over all test cases will not exceed 100,000.

Output

For each test case print YES if T1 and T2 are isomorphic and NO otherwise.

Example

Input:
2
4
4 2
4 1
2 3
4 2
2 3
4 1
5
3 4
3 2
3 5
3 1
3 4
4 2
2 5
2 1 Output: YES
NO

 < Previous 1 2 Next > acheron: 2010-11-22 14:47:31 Are there other problems involving tree isomorphism ? Hy Trường Sơn: 2010-11-11 15:40:58 Nice problem!